Currently I am using S340 Elite Nzxt, however it's too small I actually had to push in the front glass to be able to close it with the Gpu connected. The problem really is the Gpu in there is too big. I have been looking at LIAN LI PC-O11 air but not sure.
Budget under 300
Current components
I9 9900k
RTX 2080 ti evga FTW3 ultra
1tb m.2 nvme
H100i pro
Z390 Aorus Pro Wifi
2x8 3000mhz ram